Editing

Mixteca Alta, Mexico: The topography of Mixteca Alta results from the broad contact of the Sierra Madre del Sur and the Sierra Madre Oriental, two of the main Mexican mountain ranges. Dominant altitudes range between 2,000 and 2,500 m, with the highest altitude being Cerro Verde, or Nudo Mixteco (2,892 m). Soils are heavily eroded and original vegetation is restricted to small patches of oak-pine forest at higher elevations. Agriculture takes place in valley plains and hilly areas, but soil productivity is limited, partially resulting from the severe erosion and the lack of labour, due to intense emigration. The region holds the most complex geology in Mexico. According to the main themes of the site (erosion, culture and geoheritage), many of the selected geosites are related to erosionaldepositional processes and landforms associated with the intensive use of land for farming purposes. A number of geosites were selected to explain these links, including: gullies and badlands, mass wasting features, and palaeosols. Other geosites include geological contacts, plutonic and tectonic structures (dikes and sills, faults) and spheroidal weathering in outcrops. Two positive reviews of the internationally significant geological heritage were received from the IUGS.